California Wildlife Habitat Relationships System California Department of Fish and Wildlife California Interagency Wildlife Task Group GRANITE NIGHT LIZARD Xantusia henshawi Family: XANTUSIIDAE Order: SQUAMATA Class: REPTILIA R033 Written by: R. Marlow Reviewed by: T. Papenfuss Edited by: S. Granholm Updated by: CWHR Program Staff, March 2000 DISTRIBUTION, ABUNDANCE, AND SEASONALITY The granite night lizard occurs at elevations of 200 to 2250 m (660 to 7380 ft) (Lee 1976) in San Diego and western central Riverside cos., in arid and semiarid hills and down onto the desert flats. It is found exclusively in areas of massive rocks in a variety of desert, chaparral, and woodland habitats. Abundance has not been reported but a single collector must search about 1 hr in good habitats for each specimen. These lizards are active from early to mid-spring until late summer or early fall (Klauber 1926, Stebbins 1954). SPECIFIC HABITAT REQUIREMENTS Feeding: These lizards eat ants, bees, beetles, orthopterans, other insects and some vegetable matter (Brattstrom 1952, Stebbins 1954). They do not actively forage in the open. They may move about in cracks, crevices and under rocks or simply wait for the prey to come to them. Cover: This species occurs exclusively in areas of massive rocks, rock outcrops and flaking granite. It takes cover in cracks and crevices and can be found under flakes and slabs of exfoliating granite. Reproduction: This species is dependent upon cracks, crevices or sheets of exfoliating rock for cover. All reproductive activities also take place in such situations. Water: Probably not required. Pattern: This species occurs in a variety of arid and semiarid habitats dominated by massive rocks and rock outcrops. The presence of such rocky refugia is the most important habitat requirement for this species. SPECIES LIFE HISTORY Activity Patterns: The granite night lizard is diurnal. It is secretive, spending most of its time in rock cracks and crevices and under flakes. In the heat of summer, lizards may be active in late afternoon and early evening. Becomes active in early to mid-spring and remains active until late summer or early fall (Klauber 1926, Stebbins 1954, Lee 1974, Mautz and Case 1974). Seasonal Movements/Migration: No data. Home Range: No data. Territory: No data. Reproduction: Copulation occurs in May and June and egg development takes about 3 months. Broods of one or two are born live in September (Shaw 1949 Stebbins 1954). Niche: Predators probably include the larger rock-dwelling lizards (Crotaphytus, Sceloporus), snakes, and predatory birds. General Comments: The process of collecting this species by prying off flakes and widening cracks causes permanent habitat destruction. Literally tens of thousands of years must pass before the rock is again suitable. Many areas have been rendered unusable by amateur and pet collecting. REFERENCES Brattstrom, B. H. 1952. The food of the night lizards, genus Xantusia. Copeia 1952: 168-172. Klauber, L. M. 1926. Field notes on Xantusia henshawi. Copeia 1926:115-117. Lee, J. C. 1974. The duel activity cycle of the lizard, Xantusia henshawi. Copeia 1974: 934-940. Lee, J. C. 1976. Xantusia henshawi. Cat. Am. Amphibians and Reptiles 189. Mautz, W. J., and T. J. Case. 1974. A diurnal activity cycle in the granite night lizard, Xantusia henshawi. Copeia 1974:243-251. Shaw, C. E. 1949. Notes on the broods of two xantusiids, Herpetologica 5:23-26. Stebbins, R. C. 1954. Amphibians and reptiles of western North America. McGraw-Hill, New York. 536pp. R033 Life history accounts for species in the California Wildlife Habitat Relationships (CWHR) System were originally published in: Zeiner, D.C., W.F.Laudenslayer, Jr., K.E. Mayer, and M. White, eds. 1988-1990. California's Wildlife. Vol. I-III. California Depart. of Fish and Game, Sacramento, California. Updates are noted in accounts that have been added or edited since original publication. .